Field of the Invention
The present invention concerns a method for acquiring magnetic resonance image data, and a magnetic resonance apparatus and a non-transitory, computer-readable data storage medium for implementing such a method.
Description of the Prior Art
In a magnetic resonance apparatus, also called a magnetic resonance tomography system, the body to be examined of a person under examination, in particular a patient, is conventionally exposed to a relatively high basic magnetic field, for example of 1.5 or 3 or 7 tesla with the use of a basic field magnet in a scanner. In addition, gradient switchings are produced by the operation of gradient coil unit. Radio-frequency pulses, for example excitation pulses, are then emitted by a radio-frequency antenna unit by the operation of suitable antenna systems, which cause the nuclear spins of specific atoms resonantly excited by these radio-frequency pulses to be tilted by a defined flip angle with respect to the magnetic field lines of the basic magnetic field. Upon relaxation of the nuclear spins, radio-frequency signals, so-called magnetic resonance signals, are emitted, which are received by suitable radio-frequency antennas and then processed further. Finally, the desired image data can be reconstructed from the raw data acquired in this way.
For a specified measurement (data acquisition), therefore, a specific magnetic resonance sequence, also called a pulse sequence, is emitted, which is composed of a sequence of radio-frequency pulses, for example excitation pulses, preparation pulses and refocusing pulses and, at compatible times, gradient fields are emitted in different gradient axes in different spatial directions. Readout windows are set coordinated therewith in terms of time, and these specify the time frames in which the induced magnetic resonance signals are acquired. The preparation pulses may be inversion pulses, which are typically designed for suitable preparation of the relevant nuclear spins.